A catalyst for the synthesis of indoxacarb intermediate and its preparation method

Abstract

This invention discloses a catalyst for the synthesis of indoxacarb intermediates and its preparation method, belonging to the field of precious metal catalyst preparation technology. The preparation method includes the following steps: S1, adding a surfactant and 1-2 mol / L hydrochloric acid to an aqueous ethanol solution to obtain solution A; adding an aminosilane coupling agent and tetraethyl orthosilicate to the aqueous ethanol solution for hydrolysis to obtain solution B; mixing solutions A and B, then adding an ethanol solution of modified phenolic resin, reacting, washing, and freeze-drying to obtain a solid; S2, subjecting the solid obtained in S1 to low-temperature thermosetting, followed by calcination under an inert atmosphere to obtain a support; S3, mixing the support with a palladium chloride solution, shaking at room temperature, drying, and reducing under hydrogen to obtain the catalyst. This invention, through a three-step synergistic process, ultimately enables the catalyst to exhibit high activity and high selectivity in the synthesis of indoxacarb intermediates.

Description

Technical Field

[0001] This invention relates to the field of precious metal catalyst preparation, and in particular to a catalyst for the synthesis of indoxacarb intermediate and its preparation method. Background Technology

[0002] Indoxacarb is a new and highly effective insecticide. Its mechanism of action is as a sodium channel inhibitor, primarily blocking sodium channels in the nerve cells of pests, leading to coordinated paralysis and eventual death of the target pest. This product has a broad insecticidal spectrum, fast-acting, and excellent control efficacy against resistant pests such as the beet armyworm, diamondback moth, and cotton bollworm. Furthermore, this agent is non-teratogenic, non-carcinogenic, and non-mutagenic, and is also very safe for birds, aquatic organisms, and non-target organisms. Due to its relatively safe handling and environmentally friendly nature, indoxacarb has replaced a portion of the market share of carbamate and organophosphate products and has become a current research hotspot.

[0003] There are various synthetic routes and methods for indoxacarb. Taking the catalytic hydrogenation of the indoxacarb intermediate 2-(phenylmethyl)-7-chloroindo[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)-dicarboxylic acid 4a methyl ester (YCW-5) as an example, the intermediate 7-chloro-2,5-dihydroindo[1,2-e][1,3,4]oxadiazine-4a(3H)-carboxylic acid methyl ester (YCW-6) is prepared. In this reaction, debenzylated carbonylation is the key step, and the catalyst used is mainly 10% palladium on carbon. Dechlorination occurs simultaneously with deoxycarbonylation.

[0004] Patent CN110694643B provides a palladium catalyst for the synthesis of indoxacarb intermediates and its preparation method. This patent uses a mixture of activated carbon and carbon nanotubes as a support, which allows the active component particles of the catalyst to be distributed over a large range, playing an important role in the stability of the catalyst. However, the support has problems such as disordered pores, which will affect the loading of palladium and lead to a decrease in catalytic performance. Summary of the Invention

[0005] This invention provides a catalyst for the synthesis of indoxacarb intermediates and its preparation method, which can solve the problems in the background technology, such as disordered pores in the support, which will affect the loading of palladium and lead to a decrease in catalytic performance.

[0006] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a catalyst for the synthesis of indoxacarb intermediates, comprising the following steps: S1. Add surfactant and 1-2 mol / L hydrochloric acid to an aqueous ethanol solution to obtain solution A. Add aminosilane coupling agent and tetraethyl orthosilicate to an aqueous ethanol solution for hydrolysis to obtain solution B. Mix solution A and solution B, then add an ethanol solution of modified phenolic resin, react, wash, freeze dry, and obtain a solid. S2. The solid obtained in S1 is subjected to low-temperature thermosetting, and then calcined under an inert atmosphere to obtain a support. S3. Mix the support with palladium chloride solution, shake at room temperature, dry, and reduce under hydrogen to obtain the catalyst; The modified phenolic resin is mercapto-polyethylene glycol-ethylene oxide@KH570@phenolic resin.

[0007] Further, in step S1, the surfactant is C 16 H 33 EO 10 (Brij56), C 16 H 33 EO 20 C 18 H 37 EO 10 (Brij76), EO 20 PO 70 EO 20 One or more of (P123).

[0008] Further, in step S1, the ratio of surfactant, hydrochloric acid, and aqueous ethanol solution in solution A is 2-3g:1g:10-20mL; the volume ratio of anhydrous ethanol to deionized water in the aqueous ethanol solution is 9:1.

[0009] Further, in step S1, the ratio of aminosilane coupling agent, tetraethyl orthosilicate, and aqueous ethanol solution in solution B is 1-1.4g:3g:10-20mL; the volume ratio of anhydrous ethanol to deionized water in the aqueous ethanol solution is 9:1.

[0010] Further, in step S1, the aminosilane coupling agent in solution B is either 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

[0011] Further, in step S1, the volume ratio of solution A to solution B and the ethanol solution of modified phenolic resin is 1:1:(1-1.5).

[0012] Further, in step S1, the ratio of modified phenolic resin to aqueous ethanol in the ethanol solution is 20-30g:80mL; the volume ratio of anhydrous ethanol to deionized water in the aqueous ethanol solution is 9:1.

[0013] Furthermore, in step S1, the hydrolysis temperature is 20-45℃ and the hydrolysis time is 1-4h.

[0014] Furthermore, in step S1, the reaction temperature is 50-60℃ and the reaction time is 1-2h.

[0015] Further, in step S1, the method for preparing the modified phenolic resin is as follows: S11. Add phenol to a three-necked flask, heat to 40-45℃, then add 30% NaOH solution, heat to 60-65℃ within 30 min, add 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 97-100℃, boil and reflux for 10 min, stir, keep warm for 20-30 min, dehydrate under reduced pressure, then add KH570, react at 80℃ for 2-3 h, cool, extract, and dry to obtain KH570@phenolic resin; S12. KH570@phenolic resin, mercapto-polyethylene glycol-ethylene oxide, and photoinitiator 1173 are added to dichloromethane and subjected to ultraviolet light reaction. After washing and drying, modified phenolic resin is obtained.

[0016] Further, in step S11, the ratio of phenol, NaOH solution, formaldehyde solution, and KH570 is 26g:10mL:26mL:1-1.4g.

[0017] Further, in step S12, the ratio of KH570@phenolic resin, mercapto-polyethylene glycol-ethylene oxide, photoinitiator 1173, and dichloromethane is 1g:0.3-0.4g:0.13-0.2mL:100mL.

[0018] Further, in step S12, the molecular weight of the mercapto-polyethylene glycol-ethylene oxide is 0.8-1K.

[0019] Further, in step S12, the light intensity of the ultraviolet light reaction is 2.5 mW / cm². 2 The ultraviolet light wavelength is 365nm, and the illumination time is 0.5-1h.

[0020] Furthermore, in step S2, the temperature of the low-temperature thermosetting is 40-80℃, and the low-temperature thermosetting time is 12-48h.

[0021] Furthermore, in step S2, the inert atmosphere is any one of nitrogen, argon, or helium.

[0022] Furthermore, in step S2, the calcination temperature is 400-500℃, and the calcination time is 6-10h.

[0023] Further, in step S3, the ratio of the carrier to the palladium chloride solution is 0.3-0.4g:6-8mL; the concentration of the palladium chloride solution is 0.01g / mL.

[0024] Furthermore, in step S3, the reduction temperature is 400-450℃ and the time is 4-6 hours.

[0025] Secondly, the present invention provides a catalyst for the synthesis of indoxacarb intermediates, which is prepared by any one of the preparation methods described above.

[0026] The beneficial effects of this invention are: In step S1 of this invention, an inorganic framework constructed from tetraethyl orthosilicate is assembled with functional sites introduced by an aminosilane coupling agent through a sol-gel process catalyzed by 1-2 mol / L hydrochloric acid, guided by a surfactant template. Then, the template affinity of the PEG chains in the modified phenolic resin is utilized to achieve uniform distribution of the organic phase, and covalent bonding occurs between the epoxy groups and the inorganic network, thereby achieving strong interfacial composite and fine structural control of the organic-inorganic phase at the nanoscale. Finally, freeze-drying locks in this multi-level structure, laying a material foundation with a complete structure, strong interface, and abundant pores for subsequent carbonization and loading of active components. In step S2, the resin network is strengthened by low-temperature thermosetting, followed by calcination in an inert atmosphere to remove the template and carbonize the resin, transforming the precursor into a structurally stable composite support with ordered mesopores, nitrogen-sulfur doped carbon layers, and a silica framework. In step S3, the synergistic properties of this support (high specific surface area, nitrogen-sulfur species anchoring sites, and carbon-silicon heterojunction) are utilized to achieve efficient adsorption and in-situ reduction of palladium ions, obtaining a highly dispersed and strongly stable palladium nanoparticle catalyst. The three-step synergistic process ultimately enables the catalyst to exhibit high activity and high selectivity in the synthesis of indoxacarb intermediates. In particular, this invention creatively employs modified phenolic resin, which can improve the catalytic performance of the catalyst, as detailed below: 1. The modified phenolic resin of this invention is mercapto-polyethylene glycol-ethylene oxide@KH570@phenolic resin. After subsequent calcination, a nitrogen-sulfur co-doped carbon layer can be formed. The large number of defects generated by the doping is more conducive to the stable binding of palladium metal nanoparticles and the support. The strong interaction between nitrogen, sulfur and metal ensures the high stability of the catalyst, thereby improving the catalytic efficiency of the catalyst.

[0027] 2. The modified phenolic resin of this invention contains epoxy groups and polyethylene glycol. The epoxy groups can react with the amino groups of aminosilanes in the inorganic precursor network, which is equivalent to installing a strong "chemical rivet" between the organic phenolic resin and the inorganic silica network. The interfacial strength of this covalent bond is much higher than that of traditional physical adsorption or hydrogen bonding. It can effectively prevent interfacial peeling or pore collapse caused by the mismatch of two-phase shrinkage during subsequent drying, thermosetting and high-temperature calcination, thereby ensuring the integrity of the support structure, forming a uniform carbon layer, and making the dispersibility of the loaded palladium metal higher, which helps to improve catalytic performance. The polyethylene glycol and the polyoxyethylene segments of the surfactant template used in this invention are highly homologous in chemical structure. They can generate a "homogeneous mutual solubility" effect through strong hydrogen bonding and segment entanglement. This ensures the uniform dispersion of the modified phenolic resin in the composite system, which is the basis for avoiding macroscopic phase separation and obtaining a homogeneous precursor. It also helps to form a uniform carbon layer, further optimize the loading and dispersion of palladium metal, and ultimately improve catalytic performance. Detailed Implementation

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0029] In a first aspect, the present invention provides a method for preparing a catalyst for the synthesis of indoxacarb intermediates, comprising the following steps: S1. Add surfactant and 1-2 mol / L hydrochloric acid to an aqueous ethanol solution to obtain solution A. Add aminosilane coupling agent and tetraethyl orthosilicate to an aqueous ethanol solution for hydrolysis to obtain solution B. Mix solution A and solution B, then add an ethanol solution of modified phenolic resin, react, wash, freeze dry, and obtain a solid. Step S1 involves assembling an inorganic framework constructed from tetraethyl orthosilicate with functional sites introduced by an aminosilane coupling agent through a sol-gel process catalyzed by 1-2 mol / L hydrochloric acid, guided by a surfactant template. Then, the template affinity of the PEG chains in the modified phenolic resin is utilized to achieve uniform distribution of the organic phase, and covalent bonding occurs between the epoxy groups and the inorganic network, thus realizing strong interfacial composites and fine structural control of the organic-inorganic phase at the nanoscale. Finally, freeze-drying locks in this multi-level structure, laying a solid, structurally robust, and porous material foundation for subsequent carbonization and loading of active components. S2. The solid obtained in S1 is subjected to low-temperature thermosetting, and then calcined under an inert atmosphere to obtain a support. By using low-temperature thermosetting to strengthen the resin network, and then calcining in an inert atmosphere to remove the template and carbonize the resin, the precursor is transformed into a composite carrier with a stable structure, consisting of ordered mesopores, nitrogen-sulfur doped carbon layers, and a silica framework. S3. Mix the support with palladium chloride solution, shake at room temperature, dry, and reduce under hydrogen to obtain the catalyst; By utilizing the synergistic properties of this carrier (high specific surface area, nitrogen and sulfur species anchoring sites, and carbon-silicon heterojunction), efficient adsorption and in-situ reduction of palladium ions are achieved, resulting in highly dispersed and strongly stable palladium nanoparticle catalysts.

[0030] The modified phenolic resin is mercapto-polyethylene glycol-ethylene oxide@KH570@phenolic resin.

[0031] In some embodiments, in step S1, the surfactant is C 16 H 33 EO 10 (Brij56), C 16 H 33 EO 20 C 18 H 37 EO 10 (Brij76), EO 20 PO 70 EO 20 One or more of the above-mentioned nonionic surfactants can be selected to self-assemble into a well-ordered micelle template in an ethanol-water system, providing ordered pore guidance for the construction of mesoporous silica-phenolic resin hybrid supports. Simultaneously, polyoxyethylene (EO) segments of different chain lengths can be adapted to the dispersion requirements of modified phenolic resins, ensuring the uniformity and controllability of the mesoporous structure of the support.

[0032] In some embodiments, in step S1, the ratio of surfactant, hydrochloric acid, and ethanol-water solution in solution A is 2-3 g: 1 g: 10-20 mL; the volume ratio of anhydrous ethanol to deionized water in the ethanol-water solution is 9:1. This ensures that the surfactant is fully dissolved and forms stable micelles, while providing a suitable acidic catalytic environment through 1-2 mol / L hydrochloric acid. Combined with the 9:1 ethanol-water system, the hydrophilic-hydrophobic balance of the system can be adjusted, avoiding surfactant aggregation or micelle structure collapse caused by excessively high / low hydrochloric acid concentrations, thus laying the foundation for subsequent silane hydrolysis.

[0033] In some embodiments, in step S1, the ratio of aminosilane coupling agent, tetraethyl orthosilicate, and ethanol-water solution in solution B is 1-1.4 g: 3 g: 10-20 mL; the volume ratio of anhydrous ethanol to deionized water in the ethanol-water solution is 9:1. This ensures a reasonable molar ratio of tetraethyl orthosilicate to aminosilane, achieving uniform construction of the siloxane skeleton; the 9:1 ethanol-water system improves the solubility of the two silanes, avoiding excessive condensation caused by excessively high local concentrations, while providing a mild medium environment for the hydrolysis reaction, ensuring the uniform formation of silanol groups.

[0034] In some embodiments, in step S1, the aminosilane coupling agent in solution B is either 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane. It can generate silanol groups through hydrolysis of siloxane bonds, which then condense with tetraethyl orthosilicate to form a siloxane framework. Simultaneously, the introduced amino groups can form covalent bonds with the epoxy groups of the modified phenolic resin, strengthening the organic-inorganic interphase interface and providing chelation sites for subsequent palladium ions, thus improving the stability of palladium loading.

[0035] In some embodiments, in step S1, the volume ratio of solution A to solution B and the ethanol solution of modified phenolic resin is 1:1:(1-1.5). This ensures that the proportions of the micelle template, silane precursor, and modified phenolic resin are well-matched, allowing the modified phenolic resin to be uniformly embedded in the gaps between the siloxane skeleton. This avoids phase separation due to excessive organic phase or a decrease in the mechanical strength of the carrier due to insufficient organic phase, thus ensuring the homogeneity of the hybrid system.

[0036] In some embodiments, in step S1, the ratio of modified phenolic resin to aqueous ethanol in the ethanol solution is 20-30 g: 80 mL; the volume ratio of anhydrous ethanol to deionized water in the aqueous ethanol solution is 9:1. This ensures complete dissolution of the modified phenolic resin, avoiding pore blockage caused by resin agglomeration; simultaneously, the appropriate resin concentration guarantees effective bonding with the siloxane backbone, satisfying the organic phase content requirements of the carrier without affecting the ordered structure of the micelle template due to excessive concentration.

[0037] In some embodiments, in step S1, the hydrolysis temperature is 20-45°C and the hydrolysis time is 1-4 hours. Limiting the hydrolysis temperature and time of the silicon source within this window can balance the hydrolysis and polycondensation rates, avoid excessive condensation, and thus generate silicate oligomers of suitable size and high activity, which is beneficial for subsequent ordered assembly.

[0038] In some embodiments, in step S1, the reaction temperature is 50-60°C and the reaction time is 1-2 hours. Setting the temperature and time of the co-assembly reaction within this range aims to promote sufficient interaction between the organic phenolic resin and the inorganic silicate oligomer through hydrogen bonds, van der Waals forces, or chemical bonds, thereby achieving uniform hybridization and initial curing of the two phases.

[0039] In some embodiments, the method for preparing the modified phenolic resin in step S1 is as follows: S11. Add phenol to a three-necked flask, heat to 40-45℃, then add 30% NaOH solution, heat to 60-65℃ within 30 min, add 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 97-100℃, boil and reflux for 10 min, stir, keep warm for 20-30 min, dehydrate under reduced pressure, then add KH570, react at 80℃ for 2-3 h, cool, extract, and dry to obtain KH570@phenolic resin; This step uses 30% NaOH to provide a strongly alkaline environment. First, the ortho- and para-hydrogens on the benzene ring of phenol are activated at 40-45℃. Then, the temperature is raised to 60-65℃, and formaldehyde solution is added dropwise. Formaldehyde undergoes nucleophilic addition with phenol to form hydroxymethylphenol. The temperature is then raised further to 97-100℃ and refluxed to boiling. The hydroxymethylphenols undergo dehydration condensation to form a phenolic resin prepolymer containing active hydroxymethyl groups. After holding at this temperature, dehydration is performed under reduced pressure to remove free water and unreacted formaldehyde. Finally, KH570 is added, utilizing the residual moisture in the system to promote KH570 reaction. KH570 is hydrolyzed to generate silanol groups, which undergo dehydration condensation with the hydroxymethyl group of the phenolic resin to form stable covalent bonds. At the same time, the methacryloyloxy double bond in the KH570 molecule is grafted onto the resin molecular chain. After cooling, extraction and drying, the resulting KH570@phenolic resin not only introduces double bond active sites that can be used for subsequent mercapto-alkene click reactions, but also enhances the interfacial compatibility between the resin and the inorganic silicon support through siloxane bonds, laying the structural foundation for the preparation of highly dispersed palladium catalysts.

[0040] S12. KH570@phenolic resin, mercapto-polyethylene glycol-ethylene oxide, and photoinitiator 1173 are added to dichloromethane and subjected to ultraviolet light reaction. After washing and drying, modified phenolic resin is obtained.

[0041] Under ultraviolet light irradiation and the action of photoinitiator 1173, the thiol (-SH) at the end of the mercapto-polyethylene glycol-ethylene oxide chain generates sulfur radicals. These radicals undergo a highly efficient "thiol-ene" click chemistry reaction with the carbon-carbon double bonds (C=C) grafted into the KH570@phenolic resin, forming stable CS covalent bonds. This chemically grafts the polyethylene glycol-ethylene oxide chain onto the phenolic resin backbone, resulting in a doubly modified phenolic resin. The grafted long polyethylene glycol chain significantly enhances the resin's hydrophilicity and compatibility in polar systems, while the terminal ethylene oxide group provides the support with active sites for further ring-opening reactions with components such as aminosilanes. The sulfur content of the mercapto-polyethylene glycol-ethylene oxide chain allows for the formation of a sulfur-doped carbon layer during subsequent sintering. This design greatly optimizes the interfacial properties and pore microenvironment of the final carbon-silicon composite support, which is beneficial for improving the dispersion, stability, and reaction mass transfer efficiency of the active metal palladium, thereby enhancing catalytic performance.

[0042] In some embodiments, in step S11, the ratio of phenol, NaOH solution, formaldehyde solution, and KH570 is 26g:10mL:26mL:1-1.4g. This ensures that the alkali-catalyzed hydroxymethylation and polycondensation reactions proceed fully, while achieving efficient grafting of KH570 and avoiding raw material waste or insufficient modification.

[0043] In some embodiments, in step S12, the ratio of KH570@phenolic resin, mercapto-polyethylene glycol-ethylene oxide, photoinitiator 1173, and dichloromethane is 1g:0.3-0.4g:0.13-0.2mL:100mL. This forms a molecularly homogeneous dispersion system, ensuring that the photoinitiated mercapto-olefin click reaction proceeds efficiently and fully.

[0044] In some embodiments, in step S12, the molecular weight of the mercapto-polyethylene glycol-ethylene oxide is 0.8-1K. Within this molecular weight range, the grafted segments can effectively improve compatibility and will not obstruct the pores due to excessive chain length.

[0045] In some embodiments, in step S12, the light intensity of the ultraviolet light reaction is 2.5 mW / cm². 2 The ultraviolet light wavelength is 365nm, and the irradiation time is 0.5-1h. It can accurately activate photoinitiator 1173, efficiently trigger the mercapto-alkene click reaction, and avoid side reactions such as mercapto oxidation caused by excessive light irradiation.

[0046] In some embodiments, in step S2, the temperature for low-temperature thermosetting is 40-80°C, and the low-temperature thermosetting time is 12-48 hours. This promotes full cross-linking of the modified phenolic resin, enhances the interfacial bonding force with the siloxane backbone, and avoids premature carbonization of the resin caused by high temperature.

[0047] In some embodiments, in step S2, the inert atmosphere is any one of nitrogen, argon, or helium. This isolates oxygen, prevents the modified phenolic resin from oxidizing and degrading during calcination, and ensures the integrity of the carrier's mesoporous structure and active sites.

[0048] In some embodiments, in step S2, the calcination temperature is 400-500℃, and the calcination time is 6-10 hours. This enables controllable carbonization of modified phenolic resin, constructs a stable carbon-silicon composite carrier, and retains abundant active chelating sites.

[0049] In some embodiments, in step S3, the ratio of the carrier to the palladium chloride solution is 0.3-0.4 g: 6-8 mL; the concentration of the palladium chloride solution is 0.01 g / mL. This allows for uniform anchoring of palladium ions at the active sites of the carrier, ensuring appropriate palladium loading and good dispersion.

[0050] In some embodiments, in step S3, the reduction temperature is 400-450℃ and the time is 4-6 hours. This can efficiently reduce palladium ions into highly active palladium nanoparticles while avoiding palladium particle agglomeration and sintering caused by excessively high temperature or time.

[0051] Secondly, the present invention provides a catalyst for the synthesis of indoxacarb intermediates, which is prepared by any one of the preparation methods described above.

[0052] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0053] Preparation Example 1

[0054] The preparation method of the modified phenolic resin in this preparation example is as follows: S11. Add 26g of phenol to a three-necked flask, heat to 40℃, then add 10mL of 30% NaOH solution, heat to 60℃ within 30min, add 26mL of 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 97℃, boil and reflux for 10min, stir, keep warm for 20min, dehydrate under reduced pressure, then add 1g of KH570, react at 80℃ for 2h, cool, extract, dry, to obtain KH570@phenolic resin; S12. Add 1g KH570@phenolic resin, 0.3g mercapto-polyethylene glycol-ethylene oxide (molecular weight 0.8K), and 0.13mL photoinitiator 1173 to 100mL dichloromethane and carry out ultraviolet light irradiation reaction at a light intensity of 2.5mW / cm². 2 The modified phenolic resin was obtained by irradiating it with ultraviolet light at a wavelength of 365 nm for 0.5 h, washing, and drying.

[0055] Preparation Example 2

[0056] The preparation method of the modified phenolic resin in this preparation example is as follows: S11. Add 26g of phenol to a three-necked flask, heat to 42℃, then add 10mL of 30% NaOH solution, heat to 62℃ within 30min, add 26mL of 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 98℃, boil and reflux for 10min, stir, keep warm for 25min, dehydrate under reduced pressure, then add 1.2g of KH570, react at 80℃ for 2.5h, cool, extract, and dry to obtain KH570@phenolic resin; S12. Add 1g KH570@phenolic resin, 0.35g mercapto-polyethylene glycol-ethylene oxide (molecular weight 0.9K), and 0.17mL photoinitiator 1173 to 100mL dichloromethane and carry out ultraviolet light irradiation reaction at a light intensity of 2.5mW / cm². 2 The modified phenolic resin was obtained by irradiating it with ultraviolet light at a wavelength of 365 nm for 0.8 h, washing, and drying.

[0057] Preparation Example 3

[0058] The preparation method of the modified phenolic resin in this preparation example is as follows: S11. Add 26g of phenol to a three-necked flask, heat to 45℃, then add 10mL of 30% NaOH solution, heat to 65℃ within 30min, add 26mL of 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 100℃, boil and reflux for 10min, stir, keep warm for 30min, dehydrate under reduced pressure, then add 1.4g of KH570, react at 80℃ for 3h, cool, extract, and dry to obtain KH570@phenolic resin; S12. Add 1g KH570@phenolic resin, 0.4g mercapto-polyethylene glycol-ethylene oxide (molecular weight 1K), and 0.2mL photoinitiator 1173 to 100mL dichloromethane and carry out ultraviolet light irradiation reaction at a light intensity of 2.5mW / cm². 2 The modified phenolic resin was obtained by irradiating it with ultraviolet light at a wavelength of 365 nm for 1 hour, followed by washing and drying.

[0059] Compare with Example 1

[0060] The only difference between this comparative example and preparation example 1 is that "mercapto-polyethylene glycol-hydroxyl (molecular weight 0.8K)" was replaced with an equal amount of "mercapto-polyethylene glycol-ethylene oxide (molecular weight 0.8K)".

[0061] Compare with Example 2

[0062] The only difference between this comparative example and preparation example 1 is that mercapto-polyethylene glycol-ethylene oxide is omitted. The specific steps are as follows: 26g of phenol was added to a three-necked flask and heated to 40℃. Then, 10mL of 30% NaOH solution was added, and the temperature was raised to 60℃ within 30min. 26mL of 30% formaldehyde solution was added dropwise, and the temperature was raised to 85℃. Stirring was stopped, and the temperature was raised to 97℃. After boiling and reflux for 10min, the mixture was stirred and kept at this temperature for 20min. The mixture was then dehydrated under reduced pressure, and 1g of KH570 was added. The mixture was reacted at 80℃ for 2h, then cooled, extracted, and dried to obtain KH570@phenolic resin, i.e., modified phenolic resin.

[0063] Compare with Example 3

[0064] The only difference between this comparative example and preparation example 1 is that mercapto-polyethylene glycol-ethylene oxide and KH570 are omitted. The specific steps are as follows: Add 26g of phenol to a three-necked flask, heat to 40℃, then add 10mL of 30% NaOH solution, heat to 60℃ within 30min, add 26mL of 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 97℃, boil and reflux for 10min, stir, keep warm for 20min, dehydrate under reduced pressure, cool, extract, and dry to obtain phenolic resin.

[0065] Example 1

[0066] This embodiment provides a method for preparing a catalyst for the synthesis of indoxacarb intermediates, comprising the following steps: S1. Add 2g of surfactant P123 and 1g of 1mol / L hydrochloric acid to 10mL of ethanol-water solution, with an anhydrous ethanol to deionized water volume ratio of 9:1, to obtain solution A; add 1g of aminosilane coupling agent and 3g of tetraethyl orthosilicate to 10mL of ethanol-water solution (with an anhydrous ethanol to deionized water volume ratio of 9:1), and hydrolyze at 20℃ for 1h to obtain solution B; mix 10mL of solution A and 10mL of solution B, then add 10mL of ethanol solution of the modified phenolic resin obtained in Preparation Example 1 (with a modified phenolic resin to ethanol-water solution volume ratio of 20g:80mL, and an anhydrous ethanol to deionized water volume ratio of 9:1), react at 50℃ for 1h, wash, and freeze-dry to obtain a solid; S2. The solid obtained in S1 was subjected to low-temperature thermosetting at 40℃ for 12 hours, and then calcined at 400℃ for 6 hours under an argon atmosphere to obtain the support. S3. Mix 0.3 g of support with 6 mL of 0.01 g / mL palladium chloride solution, shake at room temperature, dry, and reduce at 400 °C for 4 h under hydrogen to obtain the catalyst.

[0067] Example 2

[0068] This embodiment provides a method for preparing a catalyst for the synthesis of indoxacarb intermediates, comprising the following steps: S1. 2.5 g of surfactant P123 and 1 g of 1.5 mol / L hydrochloric acid were added to 15 mL of an ethanol-water solution, with an anhydrous ethanol to deionized water volume ratio of 9:1, to obtain solution A. 1.25 g of aminosilane coupling agent and 3 g of tetraethyl orthosilicate were added to 15 mL of an ethanol-water solution (anhydrous ethanol to deionized water volume ratio of 9:1), and hydrolyzed at 35 °C for 2 h to obtain solution B. 15 mL of solution A and 15 mL of solution B were mixed, and then 18 mL of the ethanol solution of the modified phenolic resin obtained in Preparation Example 1 was added (the volume ratio of modified phenolic resin to ethanol-water solution in the ethanol solution of the modified phenolic resin was 25 g: 80 mL, and the volume ratio of anhydrous ethanol to deionized water in the ethanol-water solution was 9:1). The mixture was reacted at 55 °C for 1.5 h, washed, and freeze-dried to obtain a solid. S2. The solid obtained in S1 was subjected to low-temperature thermosetting at 60℃ for 25 hours, and then calcined at 450℃ for 8 hours under an argon atmosphere to obtain the support. S3. Mix 0.35 g of support with 7 mL of 0.01 g / mL palladium chloride solution, shake at room temperature, dry, and reduce at 420 °C for 5 h under hydrogen to obtain the catalyst.

[0069] Example 3

[0070] This embodiment provides a method for preparing a catalyst for the synthesis of indoxacarb intermediates, comprising the following steps: S1. Add 3g of surfactant P123 and 1g of 2mol / L hydrochloric acid to 20mL of ethanol-water solution, with an anhydrous ethanol to deionized water volume ratio of 9:1, to obtain solution A; add 1.4g of aminosilane coupling agent and 3g of tetraethyl orthosilicate to 20mL of ethanol-water solution (with an anhydrous ethanol to deionized water volume ratio of 9:1), and hydrolyze at 45℃ for 4h to obtain solution B; mix 20mL of solution A and 20mL of solution B, then add 30mL of ethanol solution of the modified phenolic resin obtained in Preparation Example 1 (with a modified phenolic resin to ethanol-water solution volume ratio of 30g:80mL, and an anhydrous ethanol to deionized water volume ratio of 9:1), react at 60℃ for 2h, wash, and freeze-dry to obtain a solid; S2. The solid obtained in S1 was subjected to low-temperature thermosetting at 80℃ for 48 hours, and then calcined at 500℃ for 10 hours under an argon atmosphere to obtain the support. S3. Mix 0.4 g of support with 8 mL of 0.01 g / mL palladium chloride solution, shake at room temperature, dry, and reduce at 450 °C for 6 h under hydrogen to obtain the catalyst.

[0071] Example 4

[0072] The only difference between this embodiment and Example 3 is that "the modified phenolic resin obtained in Example 1" is changed to "the modified phenolic resin obtained in Example 2".

[0073] Example 5

[0074] The only difference between this embodiment and Example 3 is that "the modified phenolic resin obtained in Example 1" is changed to "the modified phenolic resin obtained in Example 3".

[0075] Comparative Example 1

[0076] The only difference between this comparative example and Example 1 is that "the modified phenolic resin obtained in Preparation Example 1" is changed to "the modified phenolic resin obtained in Control Example 1".

[0077] Comparative Example 2

[0078] The only difference between this comparative example and Example 1 is that "the modified phenolic resin obtained in Example 1" is changed to "the modified phenolic resin obtained in Comparative Example 2".

[0079] Comparative Example 3

[0080] The only difference between this comparative example and Example 1 is that "the modified phenolic resin obtained in Example 1" is changed to "the phenolic resin obtained in Comparative Example 3".

[0081] The catalysts prepared in Examples 1-5 and Comparative Examples 1-3 of this invention were used to synthesize indoxacarb intermediates, and the performance of the catalysts was evaluated. The specific method was as follows: In a 250 mL stainless steel reactor, 15 g of the raw material 2-(phenylmethyl)-7-chloroindo[1,2-e][1,3,4]oxadiazine-2,4a(3H,5H)-dicarboxylic acid-4a-methyl ester, 150 mL of methyl acetate, 0.8 g of sodium acetate, and 0.15 g of catalyst were added. The reactor was sealed, and the air inside was replaced three times with nitrogen, followed by three times with hydrogen. The temperature was controlled at 10 °C and the hydrogen pressure at 0.1 MPa. Stirring was started at a rate of 500 r / min. After 8 h of reaction, the reaction was stopped, the reaction solution was removed, and the catalyst was removed by filtration. The filtrate was analyzed by liquid chromatography, and the results are shown in Table 1 below. Table 1

[0082] As can be seen from Table 1, the catalysts prepared in Examples 1-5 significantly improved the conversion rate and product yield of indoxacarb intermediates compared to the comparative example, while significantly reduced the dechlorination impurities compared to the comparative example. This indicates that the catalysts prepared in this invention have the characteristics of high product conversion rate, high product yield, and few by-products in the synthesis of indoxacarb intermediates.

[0083] Compared with Example 1, Comparative Example 1 lacks epoxy groups, resulting in lower raw material conversion and product yield, and higher dechlorination impurities. This indicates that epoxy groups can react with the amino groups of aminosilanes in the inorganic precursor network. This is equivalent to installing a strong "chemical rivet" between the organic phenolic resin and the inorganic silica network. The interfacial strength of this covalent bond is much higher than that of traditional physical adsorption or hydrogen bonding. It can effectively prevent interfacial peeling or pore collapse caused by the mismatch of two-phase shrinkage during subsequent drying, thermosetting, and high-temperature calcination, thereby ensuring the integrity of the support structure, forming a uniform carbon layer, and making the supported palladium metal more dispersed, which helps to improve catalytic performance.

[0084] Compared with Example 1, Comparative Example 2 lacked mercapto-polyethylene glycol-ethylene oxide, resulting in lower raw material conversion and product yield, and higher dechlorination impurities. This indicates that the nitrogen-sulfur co-doped carbon layer, with its numerous defects, is more conducive to the stable bonding of palladium metal nanoparticles with the support. The strong interaction between nitrogen, sulfur, and the metal ensures the high stability of the catalyst, thereby improving its catalytic efficiency. Furthermore, the polyethylene glycol and the polyoxyethylene segments of the surfactant template used in this invention are highly homologous in chemical structure, and can generate a "homogeneous mutual solubility" effect through strong hydrogen bonds and segment entanglement. This ensures the uniform dispersion of the modified phenolic resin in the composite system, which is the basis for avoiding macroscopic phase separation and obtaining a homogeneous precursor. It also helps to form a uniform carbon layer, further optimizing the loading and dispersion of palladium metal, and ultimately improving catalytic performance.

[0085] Compared with Example 1, Comparative Example 3, which omitted mercapto-polyethylene glycol-ethylene oxide and KH570, had the worst catalytic performance.

[0086] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for the synthesis of indoxacarb intermediates, characterized in that, Includes the following steps: S1. Add surfactant and 1-2 mol / L hydrochloric acid to an aqueous ethanol solution to obtain solution A. Add aminosilane coupling agent and tetraethyl orthosilicate to an aqueous ethanol solution for hydrolysis to obtain solution B. Mix solution A and solution B, then add an ethanol solution of modified phenolic resin, react, wash, freeze dry, and obtain a solid. S2. The solid obtained in S1 is subjected to low-temperature thermosetting, and then calcined under an inert atmosphere to obtain a support. S3. Mix the support with palladium chloride solution, shake at room temperature, dry, and reduce under hydrogen to obtain the catalyst; The modified phenolic resin is mercapto-polyethylene glycol-ethylene oxide@KH570@phenolic resin.

2. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, In step S1, the surfactant is C 16 H 33 EO 10 (Brij56), C 16 H 33 EO 20 C 18 H 37 EO 10 (Brij76), EO 20 PO 70 EO 20 One or more of (P123).

3. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, In step S1, the ratio of surfactant, hydrochloric acid, and ethanol aqueous solution in solution A is 2-3g:1g:10-20mL; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 9:

1. The ratio of aminosilane coupling agent, tetraethyl orthosilicate, and ethanol aqueous solution in solution B is 1-1.4g:3g:10-20mL; the volume ratio of anhydrous ethanol to deionized water in the ethanol aqueous solution is 9:

1. The aminosilane coupling agent in solution B is either 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

4. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, In step S1, the volume ratio of solution A to solution B and the ethanol solution of modified phenolic resin is 1:1:(1-1.5). The ratio of modified phenolic resin to aqueous ethanol in the ethanol solution is 20-30 g: 80 mL; the volume ratio of anhydrous ethanol to deionized water in the aqueous ethanol solution is 9:

1.

5. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, In step S1, the hydrolysis temperature is 20-45℃ and the hydrolysis time is 1-4h; The reaction temperature is 50-60℃, and the reaction time is 1-2 hours.

6. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, The modified phenolic resin is prepared by: S11. Add phenol to a three-necked flask, heat to 40-45℃, then add 30% NaOH solution, heat to 60-65℃ within 30 min, add 30% formaldehyde solution dropwise, heat to 85℃, stop stirring, continue heating to 97-100℃, boil and reflux for 10 min, stir, keep warm for 20-30 min, dehydrate under reduced pressure, then add KH570, react at 80℃ for 2-3 h, cool, extract, and dry to obtain KH570@phenolic resin; S12. KH570@phenolic resin, mercapto-polyethylene glycol-ethylene oxide, and photoinitiator 1173 are added to dichloromethane and subjected to ultraviolet light reaction. After washing and drying, modified phenolic resin is obtained.

7. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 6, characterized in that, In step S11, the ratio of phenol, NaOH solution, formaldehyde solution, and KH570 is 26g:10mL:26mL:1-1.4g; In step S12, the ratio of KH570@phenolic resin, mercapto-polyethylene glycol-ethylene oxide, photoinitiator 1173, and dichloromethane is 1g:0.3-0.4g:0.13-0.2mL:100mL; The molecular weight of the mercapto-polyethylene glycol-ethylene oxide is 0.8-1K; The light intensity of the ultraviolet light response is 2.5 mW / cm². 2 The ultraviolet light wavelength is 365nm, and the illumination time is 0.5-1h.

8. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, In step S2, the temperature of the low-temperature thermosetting is 40-80℃, and the low-temperature thermosetting time is 12-48h; The inert atmosphere is any one of nitrogen, argon, and helium; The calcination temperature is 400-500℃, and the calcination time is 6-10h.

9. The method for preparing the catalyst for the synthesis of indoxacarb intermediate according to claim 1, characterized in that, In step S3, the ratio of the carrier to the palladium chloride solution is 0.3-0.4g:6-8mL; the concentration of the palladium chloride solution is 0.01g / mL. The reduction temperature is 400-450℃, and the time is 4-6 hours.

10. A catalyst for the synthesis of indoxacarb intermediates, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.

Images